1. |
Combine onion, water and garlic in a heavy saucepan over low heat. Cover and simmer 8 to 10 minutes, stirring frequently until water evaporates and onion is tender. |
2. |
Stir in celery and thyme and cook for 2 minutes. |
3. |
Add stock and potatoes. Increase heat to high and bring to a boil. Reduce heat to medium-low, cover and simmer for 25 minutes, or until potatoes are tender. |
4. |
Puree potato mixture in a food processor or a blender in batches, if necessary. |
5. |
Return puree to same pot. Stir in milk and simmer over low heat until heated through. |
6. |
Season with salt and pepper to taste. Serve soup sprinkled with green onions. |